The continuing radio evolution of SN 1970G

Using the Very Large Array, we have detected radio emission from the site o f SN 1970G in the Sc galaxy M101. These observations are 31 yr after the su pernova event, making SN 1970G the longest monitored radio supernova. With flux densities of 0.12 +/- 0.020 mJy at 6 cm and 0.16 +/- 0.015 mJy at 20 c m, the spectral index of -0.24 +/- 0.20 appears to have flattened somewhat when compared with the previously reported value of -056 +/- 0.11, taken in 1990. The radio emission at 20 cm has decayed since the 1990 observations with a power-law index of beta (20) (cm) = -0.28 +/- 0.13. We discuss the r adio properties of this source and compare them to those of other Type II r adio supernovae.